But, this in no way means that a non-programmer can't go it alone. I have, and am now doing it. And in the case of the lone programmer building something entirely alone and making a million dollars, what's to say he wouldn't have made $4 million dollars had he a non-technical co-founder?
I think your line of reasoning is equally as incorrect as you're implying the OP's was.
In my experience the latter is a hell of a lot more rare than the programmer learning business skills. Consequently it's far more likely to see a programmer developing a successful business solo than a non-programmer developing a successful business solo, so in my opinion you can't just flip the argument around and say it works both ways.
Note I'm not suggesting that a co-founder isn't important or valuable, simply that the argument cannot be flipped around; I'm personally looking at recruiting an old friend once my product reaches MVP because a co-founder is important for some products.